It is a tracing paper that is a tad heavier than regular tissue paper, use to trace stencils etc.
One of the talks at yesterday's quilt meeting had this shown, I wanted to try it, so went to one of the two local quilt shops here in town, since it was bag lady day there, and got some.
Will be fun trying so I can practice free motion.

I have used it a couple of times. I have pinned it onto my quilt with regular straight pins. I hated getting stabbed with those. My good friend has used the "dots" that they have and had trouble getting all the "dots' off of her quilt. Next time I use it I am going to spritz the paper with some 505 spray and see how that works.

I use it all the time for lots of things. Quilting patterns, drawing, block construction. Lots of things.

I tried using a spray to adhere it to the quilt. Unsuccessful for two reasons. The spray I used was not 505 but Duro all purpose spray adhesive (recommended by an LAQ for this purpose) and it gummed up a lot and sometimes would spray a solid stream or "clunk" of gunk. I had to finger smooth it out before I could place it onto my quilt.

The second problem was that (OK - call me DUMB) I was using it on flanel. Yeah, yeah, I know. Not one of my brightest moments.